1. Field of the Invention
Corner framing structures are described for connecting two longitudinal swimming pool extrusions having longitudinal pool-liner anchor channels and, in particular an improved two-piece corner framing element for receiving, angularly orienting, and securing longitudinal extruded pool liner-cover track extrusions for framing square corners in the field during pool construction.
2. Description of the Prior Art
Pool liner channels are typically integrated into pool coping extrusions and/or automatic pool cover track channel extrusions or both. (See Cinderella, Inc., 2009 Aluminum Coping Profile Catalogue & Price List, pp. 2-3 & 20-22; U.S. Pat. No. 6,496,990, Last, FIG. 8b, & Col. 9, ll. 52-62; & U.S. Pat. No. 7,114,297 Mathis et al, FIGS. 4 & 8.) In fact, a single extrusion may include an upward extending pool coping above an automatic pool cover track channel and a bottom pool liner channel. (Cinderella, Inc., 2009 Aluminum Coping Profile Catalogue & Price List, Page 23.)
Joining pool coping, pool-liner and combined pool-liner cover track extrusions at the corners of pools in the field is notoriously tricky to accomplish. Because of this difficulty in field construction, the pool construction industry has resorted to prefabricating pool corners with extrusions legs in the shop, and then supplying both prefabricated corner pieces and longitudinal extrusions pieces for assembly and incorporation into the pool walls. Such prefabricating pool corner extrusion pieces are relatively expensive compared to the cost of longitudinal extrusions pieces.
In addition, prefabrication of corner pieces in many instances is accomplished by bending existing extrusion using specially designed bending machines and/or notching to avoid deformation of the extrusion channels and curved coping elements as the extrusions are bent.
In U.S. Pat. No. 7,114,297, Mathis et al suggest a method for installing a modular corner piece (actually a plate with cornering side edges and a curved, pool side-edge for joining the side edges having a pool-liner anchor channel where the cornering side edges of the plate are pressed into the pool-liner anchor channels of two intersecting pool coping extrusions and fastened to form a corner where the corner piece pool-liner anchor channel aligns with those of the extrusions. (See Col. 5, ll. 50-65 & Col. 6, ll. 12-25.) However, while innovative, simply pressing a corner plate into pool-liner anchor channels of intersecting swimming pool extrusions does not assure a precise or ‘square’ corner. For precision or an assured ‘square’ corner, the corner plate and extrusions must be pre-assembled and securely fastened together, i.e. must be pre-fabricated with extrusions legs in the shop. Also, Mathis et al ignore the complication that swimming pool extrusions with pool-liner anchor channels that secure vinyl pool liners around the tops of pool walls necessarily include short longitudinal, upward projecting lands defining a bottom lip at the opening of the liner channel that mechanically captures and anchors the ‘beaded’ or seamed side edge of the pool liner within the pool-liner channel of the extrusion.